On Thu, Sep 4, 2014 at 10:03 AM, Will Deacon <[email protected]> wrote: > Hi Kees, > > On Wed, Sep 03, 2014 at 10:57:04PM +0100, Kees Cook wrote: >> This is used from set_fixmap() and clear_fixmap() via asm-generic/fixmap.h. >> Also makes sure that the fixmap allocation fits into the expected range. >> >> Based on patch by Rabin Vincent. > > [...] > >> +void __set_fixmap(enum fixed_addresses idx, phys_addr_t phys, pgprot_t prot) >> +{ >> + unsigned long vaddr = __fix_to_virt(idx); >> + pte_t *pte = pte_offset_kernel(pmd_off_k(vaddr), vaddr); >> + >> + /* Make sure fixmap region does not exceed available allocation. */ >> + BUILD_BUG_ON(FIXADDR_START + (__end_of_fixed_addresses * PAGE_SIZE) > >> + FIXADDR_END); >> + BUG_ON(idx >= __end_of_fixed_addresses); >> + >> + if (pgprot_val(prot)) >> + set_pte_at(NULL, vaddr, pte, >> + pfn_pte(phys >> PAGE_SHIFT, prot)); >> + else >> + pte_clear(NULL, vaddr, pte); >> + >> + /* >> + * Given the potential a15 tlbi errata, we can only do tlb flushes >> + * with interrupts disabled. Callers must have taken care of this. >> + */ >> + WARN_ON_ONCE(!irqs_disabled()); >> + flush_tlb_kernel_range(vaddr, vaddr + PAGE_SIZE); > > Aha, this explains why we were confusing each other! The issue is that > interrupts must be *enabled*, so this code does the exact opposite of > what we need. > > I think this got lost in a sea of double negatives during the last round > of review.
Ah! If this is the case, perhaps we can get away with local_flush_tlb_kernel_range() then? -Kees -- Kees Cook Chrome OS Security -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
